Conventionally born by a Public Land Mobile Network (PLMN) which is unstable in network quality, voice calls are weak in signal and relatively poor in effect or even be dropped or off the network.
As mobile wireless networks develop and access modes become more diversified, wireless data services get more and more popular, users can enjoy, by means of mobile wireless networks, various data services, including web browsing, social applications, instant communication and the like. Voice calls over the Internet develop gradually with instant communication software.
At present, a scheme known for the selection of a voice call bearing domain and the switching among voice call bearing domains is as follows:
a condition for the switching to a preferred service bearer network is preset, the bearing quality of a service bearer network is monitored in real time, whether or not a bearer network switching condition is met is determined according to the bearing quality of the bearer network monitored when the first message of call signaling sent from a terminal is received by a media gateway, and a network having excellent bearing quality is selected to transmit voice call services, thereby improving the quality of the service. However, the scheme has the following problems:
first, in the scheme above, the device for switching bearer networks is a media gateway which makes a determination and a selection according to the quality of the current network and a preset switching condition without the participation of a mobile phone terminal, that is, the selection and switching process is transparent to the mobile phone terminal, thus, the user cannot select a desirable network for bearing a call as the user wishes; and
secondarily, conventional signaling and messages of voice call are stilled used to continue the call after the bearer network is switched from a Public Switched Telephone Network (PSTN) to an Internet Protocol (IP) network, thus, the control mode of the voice service is unchanged.
Thus, how to combine a voice call based on the Internet with a conventional PLMN network voice call to make full use of a wireless data network for bearing the voice call and improving call quality and saving call fee has become a technical problem which needs to be solved urgently.